Stem cell factor protects c-kit+ human primary erythroid cells from apoptosis.

OBJECTIVE: It has been reported that stem cell factor (SCF) promotes cell survival in primary cultured human erythroid colony-forming cells (ECFC). Given the heterogeneous nature of ECFC, which may affect interpretation of the data, we purified c-kit+ ECFC and investigated the specificity and mechanisms of the anti-apoptotic effects of SCF on these cells. MATERIALS AND METHODS: Glycophorin A+ (GPA+) c-kit+ cells were purified from primary cultured ECFC derived from purified human CD34+ cells. The GPA+c-kit- and nonerythroid cells were generated from the same CD34+ cells. Apoptosis of ECFC was investigated in the absence or presence of SCF and erythropoietin (EPO) in serum-free medium. DNA fragmentation was measured with enzyme linked immunosorbent assay for oligonucleosome-sized DNA, gel electrophoresis, and annexin V labeling. Characterization of expanded cells and enriched cells was performed using multiparameter flow cytometry. For Akt assay, cells were lysed and the cleared lysates subjected to SDS-PAGE followed by Western blotting. RESULTS: In GPA+c-kit+ cells, deprivation of cytokine caused rapid DNA fragmentation within 4 hours that reached a maximum at 6 hours. This was partially but clearly prevented by SCF or EPO. In contrast, no significant DNA fragmentation was seen in GPA+c-kit- and nonerythroid cells within 24 hours. PP2, a specific Src family kinase inhibitor, but not its inactive analogue PP3, reversed the anti-apoptotic effects of SCF. PP2 also inhibited SCF-induced phosphorylation of Akt. CONCLUSION: These data indicate that SCF protects purified human GPA+c-kit+ cells from apoptosis and suggest that kit-mediated Src kinase activation is involved in Akt activation and cell survival.

Recurrence with histological transformation 40 days after autologous peripheral blood stem cell transplantation (APBSCT) for cutaneous CD30-negative large T cell lymphoma.

Localized cutaneous nontender nodules appeared on the back of a 52-year-old Japanese woman. Skin biopsy revealed atypical large T-lymphocytes infiltrating the dermis. CD30 staining was negative in tumor cells. The diagnosis was CD30-negative cutaneous large T cell lymphoma. There was no evidence of peripheral lymphadenopathy or bone marrow involvement. Six cycles of induction chemotherapy were administered and a complete clinical remission (CCR) was attained. Local irradiation was not given. As the clinical course of CD30-negative cutaneous large T cell lymphoma is recurrent and often incurable with conventional chemoradiotherapy, she received high-dose chemotherapy without total body irradiation (TBI) followed by unpurged autologous peripheral blood stem cell transplantation (APBSCT). A relapse in the skin followed 40 days after APBSCT, but tumor cells transformed into a CD30-positive anaplastic large cell lymphoma (ALCL). We question the need for TBI in conditioning and for purged stem cells for APBSCT in patients with high risk cutaneous lymphomas.

A possible role for lamivudine as prophylaxis against hepatitis B reactivation in carriers of hepatitis B who undergo chemotherapy and autologous peripheral blood stem cell transplantation for non-Hodgkin's lymphoma.

Hepatitis B virus (HBV) reactivation, a well-known complication in immunosuppressed patients, can give rise to acute hepatitis and even fatal fulminant hepatitis. Three Japanese males with non-Hodgkin's lymphoma (NHL) who were carriers of HBV received high-dose chemotherapy followed by autologous peripheral blood stem cell transplantation (PBSCT). To prevent HBV reactivation, all received oral lamivudine (150 mg/day), a nucleoside analogue, at the start of chemotherapy. All were treated at full-dose intensity, including corticosteroids, without modification of treatment regimens. All three patients completed the total course of chemotherapy and PBSCT, with no signs of HBV reactivation. Peripheral blood stem cell (PBSC) harvests and hematological recoveries after transplantation were not affected by lamivudine, which was continued for at least 16 weeks after transplantation. HBV-DNA and DNA polymerase levels remained negative/normal after discontinuation of lamivudine. Lamivudine effectively inhibits HBV replication and has few serious adverse effects, particularly those related to hematopoiesis. Thus, prophylactic use of lamivudine from initiation of chemotherapy deserves consideration in the treatment of HBV carriers who require immunosuppressive chemotherapy, and may prevent HBV reactivation.

Effective high-dose chemotherapy combined with CD34+-selected autologous peripheral blood stem cell transplantation in a patient with cutaneous CD30-negative large T cell lymphoma.

Generalized multiple cutaneous tumors developed in a 60-year-old Japanese man. Skin biopsy revealed atypical large T lymphocytes infiltrating the dermis. CD30 staining was negative in the tumor cells. The diagnosis of CD30-negative cutaneous large T cell lymphoma was made. Axial and inguinal lymphadenopathy was present, but there was no evidence of bone marrow involvement. Seven cycles of chemotherapy and local electron beam irradiation were administered and complete remission (CR) was attained. As CD30-negative cutaneous large T cell lymphoma has a poor prognosis despite intensive chemotherapy, high-dose chemotherapy followed by CD34+-selected autologous peripheral blood stem cell transplantation (CD34+-APBSCT) was prescribed. The clinical course after CD34+-selected APBSCT was complicated with CMV infection occurring twice but administration of ganciclovir resolved the symptoms. He has remained in CR for 16 months after CD34+-APBSCT. This appears to be the first case report of CD34+-APBSCT in a patient with CD30-negative cutaneous large T cell lymphoma. Bone Marrow Transplantation (2000) 25, 1315-1317.

Large scale purification of human blood CD34+ cells from cryopreserved peripheral blood stem cells, using a nylon-fiber syringe system and immunomagnetic microspheres.

Isolation of large numbers of human peripheral blood CD34+ cells could lead to therapeutic applications, including purging of malignant cells from blood cell transplantations, purging of T cells from allogeneic bone marrow, and even blood cell transplantation. This procedure has limitations if there are not sufficient numbers of progenitor cells in the leukapheresis concentrates available for selection after detection of tumor cells in apheresis products. Use of frozen/thawed peripheral blood mononuclear cell (PBMC) samples would make feasible pooling of two or even more stem cell harvests collected at different time points and the total number of CD34+ progenitor cells available would increase. We established an efficient method for purification of CD34+ cells from cryopreserved apheresis products, using a nylon-fiber syringe system and immunomagnetic microspheres. We compared purity, recovery rate and clonogenicity of CD34+ cells purified from fresh (n = 22) and cryopreserved apheresis products (n = 14), using a nylon-fiber syringe system and immunomagnetic microspheres. The purity of CD34+ cells from cryopreserved products was less than that from fresh products (85.9 +/- 14.4% vs 94.6 +/- 10.0%), but the recovery rate of CD34+ cells and colony-forming cells was comparable between fresh and cryopreserved products. One patient underwent grafting with peripheral blood CD34+ cells selected after freezing, with good success. Therefore, these cells are capable of rapidly reconstituting hematopoiesis after high-dose chemotherapy. Bone Marrow Transplantation (2000) 26, 787-793.

[Reactivation of hepatitis B virus after autologous peripheral blood stem cell transplantation in patients with positive hepatitis B surface antibodies].

Hepatitis B virus (HBV) reactivation in patients with positive hepatitis B surface antibody (HBsAb) has been reported in some cases of allogenic bone marrow transplantation, acquired immunodeficiency syndrome (AIDS), and organ transplantation. However, to our knowledge, no reports have been made on the frequency and risk factors involved in HBV reactivation after autologous peripheral blood stem cell transplantation (APBSCT). Forty seven patients who underwent APBSCT were retrospectively analyzed. Three patients who were HBsAb positive before APBSCT contracted post-transplant HBV acute hepatitis. All 3 patients had multiple myeloma. HBV DNA could not be demonstrated in preserved samples of transfused blood. Therefore, we speculated that reactivation of latent HBV had occurred. The 3 patients with HBV hepatitis had relatively lower titers of pre-transplant HBsAb, and the total dose of steroids they received after APBSCT was significantly higher than for other patients who did not experience post-transplant HBV reactivation. There were no significant differences in pre-transplant hepatitis B core antibody (HBcAb) titer or total post-transplant blood transfusion volume. Our study suggested that immunocompromised states, especially those induced by high-dose steroid therapy, may allow the reactivation of HBV after APBSCT, even in patients who had HBsAb before APBSCT.

[Successful hematologic reconstitution using CD34+ cells positively selected from cryopreserved autologous peripheral blood stem cells in a patient with malignant lymphoma].

Clinical use of CD34+ cells positively selected from cryopreserved peripheral blood stem cells (PBSC) has been limited, and there have been only a few reports of this procedure, mainly because clump formation decreases the proportion of CD34+ cells that can be recovered. A 49-year-old Japanese woman with non-Hodgkin's lymphoma (NHL) (follicular mixed, B cell, stage IVA) was treated with seven cycles of conventional chemotherapy and achieved partial remission. During hematopoietic recovery after the seventh course of chemotherapy, PBSC were harvested by continuous leukapheresis and cryopreserved. However, clonal rearrangement of the immunoglobulin heavy chain gene was detected in the PBSC by Southern blot analysis. After high-dose chemotherapy, CD34+ cells were positively immunoselected from the cryopreserved PBSC and infused into the patient at 1.97 x 10(6)/kg. The overall purity and recovery rate of the CD34+ cells were 72.2% and 65.0%, respectively. There were no severe adverse effects after PBSC transplantation, and the time required for recovery of neutrophils to over 0. 5 x 10(9)/l and platelets to over 50 x 10(9)/l was 11 and 21 days, respectively. Transplantation of CD34+ cells positively selected from cryopreserved PBSC provides engraftment ability similar to that of unmanipulated PBSC.

[Autoimmune thrombocytopenia following syngeneic peripheral blood stem cell transplantation].

A 35-year-old man with non-Hodgkin's lymphoma (NHL) (follicular small cleaved, B cell, stage IVB) received double myeloablative chemotherapy with syngeneic peripheral blood stem cell transplantation (PBSCT). Although platelet recovery was delayed until day 29 after the second transplantation, thereafter trilineage hematopoietic reconstitution was achieved. The evaluation after PBSCT did not detect any residual tumor. The patient was in good health until day 138, when his platelet count suddenly began falling; on day 150, it had fallen to 1.5 x 10(4)/microliter, and the patient was re-admitted for treatment. The bone marrow was normocellular with a normal count and megakaryocyte structure. Other examinations, including serological tests and computed tomography of the neck, chest, abdomen, and retroperitoneum, did not indicate a recurrence of NHL or reveal the cause of thrombocytopenia. The patient's platelet-associated IgG (PAIgG) level was at 70.9 ng/10(7) platelets (normal range: 9-25 ng/10(7) platelets); a diagnosis of thrombocytopenia due to an autoimmune mechanism such as idiopathic thrombocytopenic purpura (ITP) was made. Prednisolone therapy increased the platelet count and reduced the PAIgG level. Thrombocytopenia with an ITP-like mechanism rarely occurs more than 100 days after autologous or syngeneic stem cell transplantation, and should be taken into consideration as a late complication of PBSCT.

[Effective chemotherapy with docetaxel in a patient with breast cancer who had progressed after high-dose chemotherapy with autologous peripheral blood stem cell transplantation (APBSCT)].

A 39-year-old female underwent mastectomy for breast cancer in December 1995. However, two years later, she relapsed with multiple bone metastases. Only a partial response was obtained despite tandem high-dose chemotherapy with autologous peripheral blood stem cell transplantation (APBSCT). Disease progression with bone pain and an increasing in the level of serum NCC-ST439 occurred 5 months after APBSCT. Salvage chemotherapy with docetaxel 60 mg/m2 reduced her symptoms, and the level of serum NCC-ST439 decreased to within the normal range. Ten cycles of docetaxel administration were repeated without severe adverse reactions in an outpatient setting for 10 months. There is little information regarding treatment after relapse from APBSCT for breast cancer. Docetaxel may be an effective agent for patients in such a setting.

Etoposide-containing conditioning regimen reduces the occurrence of hemophagocytic lymphohistiocytosis after SCT.

Hemophagocytic lymphohistiocytosis (HLH) is a rare life-threatening disease of severe hyperinflammation caused by uncontrolled proliferation of activated lymphocytes and macrophages that secrete high amounts of inflammatory cytokines. HLH occurring after SCT is difficult to diagnose. It is characterized by severe clinical manifestations and high mortality. Despite current therapeutic approaches, outcomes remain poor. We analyzed the incidence and risk factors of HLH after SCT and the response to treatment and prognosis of 554 patients with HLH after SCT. The cumulative incidence of HLH after SCT was 4.3% (24/554). Use of etoposide in the conditioning regimen was only factor that reduced HLH after SCT (P=0.027). All patients who received autologous transplantation were successfully treated. Patients with liver dysfunction (for example, high total bilirubin level, prolonged prothrombin time and high level of fibrinogen degradation products) had a poor response to treatment for HLH. Physicians should be cautious of HLH, while not using etoposide for conditioning regimen.

Severe aplastic anemia associated with thymic carcinoma and partial recovery of hematopoiesis after thymectomy.

Aplastic anemia has been a rare complication of thymic tumors documented in only a few cases. We now report that a previously healthy, 72-year-old woman had a well-differentiated squamous cell thymic carcinoma and severe aplastic anemia, as detected on a simultaneous basis. After extirpation of the thymic carcinoma, hematological recovery was achieved. While cyclosporine (CyA), prednisolone (PSL), and methenolone improved hematological data even more, a partial and stable remission has been sustained for 22 months. The patient's serum prior to the surgery had a suppressive effect on the formation of colonies of erythroid and nonerythroid colonies, as determined using the patient's bone marrow cells and compared with the patient's serum after the surgery and normal AB serum. This case report concerns a patient in whom we observed simultaneous occurrence of a thymic tumor and a sever marrow aplasia for which we describe our therapeutic approach.

Phosphatidylinositol 3-kinase is involved in the protection of primary cultured human erythroid precursor cells from apoptosis.

Little is known about the physiologic role of phosphatidylinositol 3-kinase (PI-3K) in the development of erythrocytes. Previous studies have shown that the effects of the PI-3K inhibitor wortmannin on erythropoietin (EPO)-dependent cell lines differed depending on the cell type used. Wortmannin inhibited EPO-induced differentiation of some cell lines without affecting their proliferation; however, the EPO-induced proliferation of other cell lines was inhibited by wortmannin. In neither case were signs of apoptosis observed. We have previously reported that signaling in highly purified human colony forming units-erythroid (CFU-E), generated in vitro from CD34(+) cells, differed from that in EPO-dependent cell lines. In the current study, we examined the effects of a more specific PI-3K inhibitor (LY294002) on human CFU-E. We found that LY294002 dose-dependently inhibits the proliferation of erythroid progenitor cells with a half-maximal effect at 10 micromol/L LY294002. LY294002 at similar concentrations also induces apoptosis of these cells, as evidenced by the appearance of annexin V-binding cells and DNA fragmentation. The steady-state phosphorylation of AKT at Ser-473 that occurs as a result of PI-3K activation was also inhibited by LY294002 at similar concentrations, suggesting that the effects of LY294002 are specific. Interestingly, the acceleration of apoptosis by LY294002 was observed in the presence or absence of EPO. Further, deprivation of EPO resulted in accelerated apoptosis irrespective of the presence of LY294002. Our study confirms and extends the finding that signaling in human primary cultured erythroid cells is significantly different from that in EPO-dependent cell lines. These data suggest that PI-3K has an antiapoptotic role in erythroid progenitor cells. In addition, 2 different pathways for the protection of primary erythroid cells from apoptosis likely exist: 1 independent of EPO that is LY294002-sensitive and one that is EPO-dependent and at least partly insensitive to LY294002.